TABLE 2.

Sensitivity of the RT-PCR assay for detection of G. intestinalis cysts and C. parvum oocysts spiked into 100-μl packed pellet concentrates from river and creek samples as determined by silver-stained polyacrylamide gel electrophoresis

Spike dosea		RT-PCR resultc for:
G. intestinalis	C. parvum	Giardia	C. parvum	IPCb
340	210	+	+	+
100	62	+	+	+
31	12	+	+	+
8	2	+	+	+
2	1	+	+	+
0	0	−	−	+

^aCyst and oocyst concentrations (numbers of cysts or oocysts per sample) representing the averages from 10 spiking experiments. 

^bTen femtograms of IPC added to each reaction mixture. 

^c+, detected; −, not detected.